As an outer structure that stores a power generation element including a cathode, an anode, and an electrolyte, a so-called laminated battery which uses laminated films is known. For example, Patent Document 1 discloses a laminated battery having a recess in which a film member is accumulated at a portion of a sealing section of an outer film, at least where protruding sections of the cathode and the anode contact the film. The recess is formed along a longitudinal direction of the sealing section. Patent Document 2 discloses a laminated battery wherein, after a sealing section of an outer film is formed, the sealing section is emboss-processed, to provide protrusions and recesses.